I think it could be any of the three to be honest. I think they all have pretty high potential, and each has assets and flaws that could elevate or lower their game.
I like Rozier more and more every day I watch more of him. He's a tough SOB. That "burst" the coaches talk about it 100% legit. He has explosive athleticism. I really see him as Avery Bradley with a handle if he can develop his off-ball and shooting skills. If he does that, I think he could become a really good player. Even without it he could be a good role player. He's defense isn't recognized yet on CB, but it will be. He's tenacious, and he's NEVER scared. Perfect back-court mate for Smart if those off-ball skills develop.
Hunter seems like the prototypical SG to me. Obviously not at the same level, but he reminds me a little of Reggie Miller. Can literally shoot it from anywhere, has great size for a guard. Very high IQ, he can play both on and off the ball and he knows how to make the right play. If your hoping Smart/Rozier is your future back-court, having a guy like RJ who has different, but well fitting talents could be really good. His size is an issue. He needs to bulk up in the worst way. He's gonna have a hard time defending bigger 2's. But his instincts are very good, I can see why some think he'll be the best pro. Guys with his skill set are generally successful at the NBA level.
As far as Mickey goes, he could be quite a good player himself. He's got a chip on his shoulder now from the draft, and that could push him to be a very important player in our future. If he can continue to develop a reliable jump shot (and possibly extend to the 3) I think he could be a Draymond Green type, do it all big man. He's super athletic and defensively he can make an impact right away with his shot blocking, but he needs to work on his rotations and positioning.
It's a really hard call. I liked the guys we got in this draft, and I think they all have really good potential but I don't think anyone's head and shoulders above anyone else.